1. Field of the Invention
The invention relates generally to facsimile communication, and more specifically to validation of facsimile communication.
2. Description of the Related Art
Facsimile communication can occur between a number of different types of facsimile devices. Facsimile devices are generally configured for at least one of facsimile communication, voice communication, and a combination of facsimile communication and voice communication. Facsimile devices may also be configured for other types of communication (e.g., data communication).
Facsimile communication is often initiated when a receiving facsimile device detects a single facsimile calling tone (e.g., a CNG tone or calling tone as defined by the Group 3 facsimile protocol). In some cases, a receiving facsimile device may improperly detect a sound other than a facsimile tone (e.g., a human voice) as the facsimile calling tone. This can occur if the frequency and duration of the other sound are similar to the frequency and duration of the facsimile tone. Improper detection of a facsimile tone can lead to disruption of the intended communication (e.g., a voice communication).